2008 Microchip Technology Inc.
DS22096A-page 55
MCP453X/455X/463X/465X
7.2
Data Byte
Only the Read Command and the Write Command
have Data Byte(s).
The Write command concatenates the 8-bits of the
Data Byte with the one data bit (D8) contained in the
Command Byte to form 9-bits of data (D8:D0). The
Command Byte format supports up to 9-bits of data so
that the 8-bit resistor network can be set to Full-Scale
(100h or greater). This allows wiper connections to
Terminal A and to Terminal B. The D9 bit is currently
unused.
7.3
Error Condition
If the four address bits received (AD3:AD0) and the two
command bits received (C1:C0) are a valid combina-
tion, the MCP4XXX will Acknowledge the I2C bus.
If the address bits and command bits are an invalid
combination, then the MCP4XXX will Not Acknowledge
the I2C bus.
Once an error condition has occurred, any following
commands are ignored until the I2C bus is reset with a
Start Condition.
7.3.1
ABORTING A TRANSMISSION
A Restart or Stop condition in the expected data bit
position will abort the current command sequence and
TABLE 7-3:
COMMANDS
Command Name
# of Bits
High
Voltage
(VIHH) on
HVC pin?
29
—
29
—
20
—
20
—
29
Yes
29
Yes
20
Yes
20
Yes